Specific antiserum and monoclonal antibodies against the taurine biosynthesis enzyme cysteine sulfinate decarboxylase: identity of brain and liver enzyme.
Cysteine sulfinate decarboxylase (CSD), the putative biosynthetic enzyme for taurine, was purified 1,800-fold with a 1% yield from rat liver, where it was found to be 20-fold enriched compared with brain. The final fraction was homogeneous, as ascertained through sodium dodecyl sulfate-polyacrylamide gel electrophoresis and reverse-phase HPLC. An antiserum was raised in the rabbit that (a) quantitatively immunoprecipitated CSD activity and (b) immunolabeled only one band (MW = 51,000) on an immunoblot from liver homogenate. Monoclonal antibodies were also raised that recognized the CSD protein and immunolabeled the same 51-kilodalton protein on an immunoblot from liver homogenate. In a brain extract, two CSD activities had been previously found and named CSDI and CSDII, according to their chromatographic elution patterns. We have compared the properties of CSDI from brain--the most likely enzyme involved in the biosynthesis of taurine in the brain, according to previous investigations-and CSD from liver: Both activities (a) were similarly eluted on ion-exchange and hydroxyapatite chromatographies, (b) showed the same elution pattern on gel filtration with an apparent native molecular weight of approximately 63,000, and (c) were immunoprecipitated in a strictly identical manner by the antiserum against liver CSD. Moreover, this antiserum as well as the monoclonal antibodies immunolabeled a single band (51 kilodaltons) on an immunoblot from brain CSD-enriched fraction or liver fraction. All these data show that CSDI from brain and liver CSD are the same monomeric enzyme. They also indicate that a specific antiserum against rat liver CSD has been raised that can be used for immunocytochemical visualization of CSD-containing cells in the brain.
Remy
A
A
INSERM U. 171, Groupe de Neurochimie Fonctionnelle Centre Hospitalier Lyon-Sud, France.
Henry
S
S
Tappaz
M
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D001921:Brain / Q000201:enzymology*; D002262:Carboxy-Lyases / Q000145:classification / Q000276:immunology* / Q000302:isolation & purification; D007106:Immune Sera / Q000276:immunology*; D008099:Liver / Q000201:enzymology*; D009206:Myocardium / Q000201:enzymology; D051381:Rats; D013654:Taurine / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D007106:Immune Sera; D013654:Taurine; D002262:Carboxy-Lyases; C019972:sulfoalanine decarboxylase